Although “clink-clank” is in OED as well as plain old “clink”, making this hyphenated word is a JRRT original.

• 04.040 with a clink-clink of chains,

“clink, n.1.” OED Online. Oxford University Press, June 2017. Web. 7 September 2017.

“clink-clank, n.” OED Online. Oxford University Press, June 2017. Web. 7 September 2017.